午後

Afternoon — Grokipedia Fact-checked by Grok 2 months ago Afternoon Ara Eve Leo Sal 1x The afternoon is the portion of the day that follows noon and precedes evening, typically extending from 12:00 p.m. until approximately 5:00 or 6:00 p.m., or until sunset in some definitions. [1] [2] [3] This period marks the latter half of daylight hours in the 24-hour cycle, during which the sun descends from its zenith , and it often aligns with post-lunch routines in daily life. [4] The word "afternoon" derives from Middle English afternone or after-non , a compound of "after" and "noon," first appearing in written records around 1330, reflecting its literal meaning as the time succeeding midday . [5] [6] While the exact boundaries can vary by cultural or regional convention—such as ending at 5:00 p.m. in formal American English usage or blending into evening around sunset in more flexible interpretations—the afternoon universally signifies a transitional phase between the peak of the day and dusk . [7] [1] Culturally, the afternoon carries notable traditions that emphasize rest, socialization, and refreshment. In Britain, afternoon tea emerged in the 1840s as a light meal of tea, sandwiches, scones, and pastries, popularized by Anna, the Duchess of Bedford, to bridge the long gap between lunch and dinner ; it remains a symbol of elegance and social gathering. [8] [9] In Spanish-speaking countries like Spain and those in Latin America , the siesta —a brief nap or rest period in the early afternoon following the midday meal—has ancient roots tied to agrarian lifestyles and hot climates, promoting productivity and well-being despite modern misconceptions of it as laziness. [10] [11] These practices highlight the afternoon's role in balancing work, leisure, and circadian rhythms across societies. [12] [13] Definition and Terminology Definition The afternoon is the portion of the day that begins at noon, conventionally defined as 12:00 PM, and extends until approximately 6:00 PM or sunset, depending on cultural, regional, or contextual norms. [1] [2] This period marks the transition from the midday peak of sunlight to the onset of evening, encompassing the latter half of the typical daylight hours in most locations. [4] In distinction from morning, which precedes noon and focuses on the early daylight phase, the afternoon follows the solar zenith and leads into evening, generally considered to start after sunset or around 6:00 PM when twilight begins to dominate. [1] [7] Its boundaries are primarily clock-based in modern usage, with noon serving as the standard starting point across international time zones, where 12:00 PM aligns with local standard time for the respective zone. [14] Although solar noon—the moment the sun reaches its highest point—may vary slightly by longitude within a time zone, clock time provides a consistent global reference. [15] The duration of the afternoon varies seasonally, particularly in temperate zones, where longer days in summer extend it beyond six hours due to later sunsets (often 8:00 PM or later), while shorter winter days compress it to around four hours with sunsets as early as 4:00 PM or 5:00 PM. [16] These changes arise from Earth's axial tilt , which shifts the timing of sunrise and sunset throughout the year, affecting the length from noon to sunset without altering the fixed start at midday . [16] In equatorial regions, such variations are minimal, with afternoons remaining relatively consistent year-round at about six hours. [17] Etymology The English word "afternoon" derives from Middle English "afternone" or "after-non," a compound formed around 1300 from "after," meaning later in time, and "noon," referring to midday . [5] The earliest attested use appears around 1330 in texts such as the Middle English romance Arthour and Merlin . [6] The component "after" traces back to Old English "æfter," an adverb and preposition denoting sequence or position behind, ultimately from Proto-Germanic *after. [18] Meanwhile, "noon" originates from Latin "nona hora," the ninth hour after sunrise (approximately 3 p.m. in Roman reckoning), which shifted in meaning to exactly 12 p.m. by the 14th century due to changes in ecclesiastical and canonical timekeeping. [19] This English term evolved in parallel with Latin-influenced concepts like "post meridiem" (p.m.), meaning "after midday ," a phrase borrowed into English in the 1640s from Medieval Latin "post merīdiem," where "post" signifies after and "merīdiem" is the accusative of "merīdiēs" ( midday , from "medius diēs," middle of the day). This Latin root shaped equivalents in Romance languages ; for instance, French "après-midi" combines "après" (after) and "midi" ( noon , from Latin "medius diēs"), emerging in the 14th century to denote the period following midday . In Spanish, "tarde" (afternoon or early evening) stems from Latin "tardē," an adverb meaning "late" or "slowly," derived from the adjective "tardus" (slow, delayed), reflecting a semantic extension to later parts of the day by the medieval period. [20] Cross-linguistically, similar constructions appear in Germanic languages , such as German "Nachmittag," a compound of "nach" (after) and "Mittag" (midday, from Latin "medius diēs" via Old High German ), attested from the 16th century onward. [21] In Arabic , the term distinguishes from "aṣ-ṣabāḥ" (morning, from the root ṣ-b-ḥ denoting the time of rising or swimming in light) to equivalents like "ʿaṣr" (mid-afternoon, specifically the period when shadows equal object lengths), derived from the root ʿ-ṣ-r (to press or squeeze out), evoking the sun's declining intensity, with usage rooted in classical Islamic prayer times from the 7th century. By the 19th century , industrialization and the advent of standardized clock time—particularly through railroad schedules adopted in 1883 in North America and similar reforms in Europe —reinforced the term's alignment with fixed clock divisions, shifting its application from variable solar or customary measures to precise post-noon intervals in urban and industrial contexts. [22] Temporal Boundaries Clock-Based Division In modern timekeeping, the afternoon is typically delineated on the 12-hour clock as commencing immediately after noon, from 12:01 p.m. to 5:59 p.m., though informal usage often extends it to 6:00 p.m. to align with the onset of evening activities. [3] [2] This division reflects a conventional partitioning of the day into morning, afternoon, and evening based on mechanical clocks standardized since the 19th century , independent of solar position. [23] The equivalent in the 24-hour time format, widely adopted in military, aviation, and international contexts, spans from 12:00 to 17:59, with informal extensions to 18:00. [23] This format eliminates ambiguity between a.m. and p.m. by continuously numbering hours from 00:00 (midnight) to 23:59, ensuring precise coordination across global operations. [24] Time zones further modulate afternoon boundaries worldwide, with each of the 24 standard zones offset by one hour from Coordinated Universal Time (UTC), resulting in afternoons occurring at staggered intervals. For instance, when it is 3:00 p.m. in the UTC+0 zone (e.g., London), it is simultaneously 10:00 a.m. in the UTC-5 zone (e.g., New York) and 5:00 a.m. the following day in the UTC+14 zone (e.g., Kiritimati, Kiribati). The International Date Line, roughly aligned with the 180° meridian, introduces a full-day shift: crossing westward adds 24 hours, so an afternoon in the eastern hemisphere (e.g., 2:00 p.m. on Monday in Fiji, UTC+12) may precede the same clock time by a day in the western hemisphere (e.g., 2:00 p.m. on Sunday in American Samoa, UTC-11). [25] [26] Daylight saving time (DST), observed in over 70 countries, adjusts clock-based divisions seasonally by advancing time one hour in spring and reverting in fall, thereby shifting the afternoon period relative to solar noon. In participating regions, this effectively lengthens clock afternoons with extended evening daylight during summer months (e.g., sunset at 8:00 p.m. instead of 7:00 p.m.) and shortens them in winter by reclaiming the hour in fall, altering the duration of lit afternoon hours by one hour without changing the underlying 12:00–18:00 span. [27] [28] Solar and Astronomical Alignment In astronomical terms, the afternoon is defined as the interval following solar noon—when the Sun reaches its zenith or highest point in the sky by crossing the observer's meridian—until sunset. [15] This period corresponds to the Sun's apparent westward motion across the sky after its meridian transit. [29] The exact duration varies with geographic location and season, influenced by Earth's axial tilt and orbital position relative to the equinoxes. [30] Solar noon occurs approximately at 12:00 local solar time , determined by the observer's longitude , as Earth's rotation completes 360 degrees in 24 hours, or 15 degrees per hour. [31] To calculate it, the local time is adjusted from the standard meridian of the time zone by adding or subtracting 4 minutes for each degree of longitude difference (since 15 degrees equals one hour). However, this is further refined by the equation of time, which accounts for variations in Earth's elliptical orbit and axial tilt , causing solar noon to deviate from mean solar time by up to 16 minutes throughout the year. [32] The afternoon thus begins at this adjusted solar noon and ends at sunset, when the Sun's upper limb touches the horizon. The length of the afternoon differs markedly by latitude due to the geometry of solar illumination. Near the equator , where the Sun rises nearly due east and sets due west year-round, the afternoon consistently spans about 6 hours on equinoxes, with minor seasonal variations of less than an hour. [30] In contrast, at higher latitudes toward the poles, the afternoon's duration fluctuates dramatically; for instance, during polar summer, continuous daylight ( the